Week 5: MRI and Tendinopathy

This week we performed additional MRI scans, this time on a whole rat sent from the Andarawis-Puri Lab in Ithaca. Our lab uses a fatigue loading procedure on rat patellar tendon as a model for overuse tendinopathy. This involves clamping the patella and tibia and applying cyclical loads that induce sub-rupture fatigue damage. This model has been used to study changes in gene expression, tissue structure, and mechanical properties and has provided insight into mechanisms of disease and healing. MR imaging, including T2* quantification, could be a useful tool to determine changes in collagen alignment and water content in the patellar tendon in vivo after fatigue loading. This could lead MRI based techniques to quantitatively and non-invasively assess or diagnose tendinopathy.

One of the challenges in scanning rats is their relatively small size when compared with humans. We attempted to use a wrist coil and a custom made rat coil to improve image quality. In addition, positioning of the animal is key, especially given that our intention was to image both patellar tendons simultaneously. This was resolved using a tube and Silly Putty to precisely position the animal and its limbs. Finally, the amount of signal, dependent on the proton density of the sample, was a major concern when we first imaged dissected rat tendon. Fortunately, using the whole animal provided greater signal intensity. These strategies allowed us to get relatively clear images that I hope to analyze in the next week.

Cube MRI scan of rat knee 

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